US5579389AExpiredUtility

Histogram-based processing of audio signals

36
Assignee: INTEL CORPPriority: Nov 24, 1993Filed: Dec 20, 1994Granted: Nov 26, 1996
Est. expiryNov 24, 2013(expired)· nominal 20-yr term from priority
Inventors:Larry WagnerRobert Marshall
G06T 1/00H04M 3/568H04L 12/1813H04N 21/4143H04L 12/1822H04N 7/148H04Q 2213/13299H04Q 2213/13106H04Q 2213/13389H04M 7/006H04N 21/643H04Q 2213/13003H04Q 2213/1324H04M 3/567H04Q 2213/13204H04Q 2213/13103H04Q 2213/13209G06T 2200/16H04M 9/08H04Q 2213/13337H04N 7/15
36
PatentIndex Score
8
Cited by
54
References
28
Claims

Abstract

A local histogram is generated with a controller based on local audio signals generated with a local microphone. A level of transmit attenuation and a level of receive attenuation are generated with the controller based on the local histogram. The local audio signals are attenuated with a transmit attenuator at the level of transmit attenuation for transmission to a remote node. Remote audio signals received from the remote node are attenuated with a receive attenuator at the level of receive attenuation for playback at a local speaker.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. An apparatus for processing audio signals, comprising: (a) a transmit attenuator for attenuating local audio signals generated by a local microphone for transmission to a remote node;   (b) a receive attenuator for attenuating remote audio signals received from the remote node for playback at a local speaker; and   (c) a controller, electrically connected to the transmit attenuator and the receive attenuator, for controlling a level of transmit attenuation for the transmit attenuator and a level of receive attenuation for the receive attenuator, wherein:   the controller generates a local histogram based on the local audio signals; and   the controller uses the local histogram to generate the level of transmit attenuation and the level of receive attenuation.   
     
     
       2. The apparatus of claim 1, wherein: the controller uses the local histogram to generate a level of local background noise; and   the controller uses the level of local background noise to generate the levels of transmit and receive attenuation.   
     
     
       3. The apparatus of claim 2, wherein: the controller generates an updated level of local background noise, if a variance of the local histogram is less than a specified local threshold; and   the controller uses the updated level of local background noise to generate the levels of transmit and receive attenuation.   
     
     
       4. The apparatus of claim 3, wherein the controller generates the updated level of local background noise based on a mean of the local histogram. 
     
     
       5. The apparatus of claim 1, wherein the controller generates the local histogram based on energy levels of audio frames of the local audio signals. 
     
     
       6. The apparatus of claim 1, wherein the controller generates the local histogram as a logarithm-based histogram. 
     
     
       7. The apparatus of claim 1, wherein: the controller receives, from the remote node, remote audio information corresponding to the remote audio signals, wherein the remote audio information was generated by the remote node from a remote histogram generated by the remote node based on the remote audio signals; and   the controller uses the remote audio information and the local histogram to generate the levels of transmit and receive attenuation.   
     
     
       8. The apparatus of claim 7, wherein: the remote audio information comprises a level of remote background noise; and   the controller uses the level of remote background noise and the local histogram to generate the levels of transmit and receive attenuation.   
     
     
       9. The apparatus of claim 1, wherein: the controller generates a remote histogram based on the remote audio signals; and   the controller uses the local histogram and the remote histogram to generate the levels of transmit and receive attenuation.   
     
     
       10. The apparatus of claim 9, wherein: the controller uses the local histogram to generate a level of local background noise;   the controller uses the remote histogram to generate a level of remote background noise; and   the controller uses the level of local background noise and the level of remote background noise to generate the levels of transmit and receive attenuation.   
     
     
       11. The apparatus of claim 10, wherein: the controller generates an updated level of local background noise, if a variance of the local histogram is less than a specified local threshold;   the controller generates an updated level of remote background noise, if a variance of the remote histogram is less than a specified remote threshold; and   the controller uses the updated levels of local and remote background noise to generate the levels of transmit and receive attenuation.   
     
     
       12. The apparatus of claim 11, wherein: the controller generates the updated level of local background noise based on a mean of the local histogram; and   the controller generates the updated level of remote background noise based on a mean of the remote histogram.   
     
     
       13. The apparatus of claim 1, wherein: the controller generates the local histogram as a logarithm-based histogram based on energy levels of audio frames of the local audio signals;   the controller uses the local histogram to generate a level of local background noise;   the controller receives, from the remote node, a level of remote background noise, wherein the level of remote background noise was generated by the remote node from a remote histogram generated by the remote node based on the remote audio signals; and   the controller uses the level of local background noise and the level of remote background noise to generate the levels of transmit and receive attenuation.   
     
     
       14. The apparatus of claim 13, wherein: the controller generates an updated level of local background noise based on a mean of the local histogram, if a variance of the local histogram is less than a specified local threshold; and   the controller uses the updated level of local background noise and the level of remote background noise to generate the levels of transmit and receive attenuation.   
     
     
       15. A computer-implemented process for processing audio signals, comprising the steps of: (a) generating, with a controller, a local histogram based on local audio signals generated with a local microphone;   (b) generating, with the controller, a level of transmit attenuation and a level of receive attenuation based on the local histogram;   (c) attenuating, with a transmit attenuator at the level of transmit attenuation, the local audio signals for transmission to a remote node; and   (d) attenuating, with a receive attenuator at the level of receive attenuation, remote audio signals received from the remote node for playback at a local speaker.   
     
     
       16. The process of claim 15, wherein step (b) comprises the steps of: (1) generating a level of local background noise based on the local histogram; and   (2) generating the levels of transmit and receive attenuation based on the level of local background noise.   
     
     
       17. The process of claim 16, wherein step (b) comprises the steps of: (1) generating an updated level of local background noise, if a variance of the local histogram is less than a specified local threshold; and   (2) generating the levels of transmit and receive attenuation based on the updated level of local background noise.   
     
     
       18. The process of claim 17, wherein step (b)(1) comprises the step of generating the updated level of local background noise based on a mean of the local histogram. 
     
     
       19. The process of claim 15, wherein step (a) comprises the step of generating the local histogram based on energy levels of audio frames of the local audio signals. 
     
     
       20. The process of claim 15, wherein step (a) comprises the step of generating the local histogram as a logarithm-based histogram. 
     
     
       21. The process of claim 15, wherein step (b) comprises the steps of: (1) receiving, by the controller from the remote node, remote audio information corresponding to the remote audio signals, wherein the remote audio information was generated by the remote node from a remote histogram generated by the remote node based on the remote audio signals; and   (2) generating the levels of transmit and receive attenuation using the remote audio information and the local histogram.   
     
     
       22. The process of claim 21, wherein: the remote audio information comprises a level of remote background noise; and   step (b)(2) comprises the step of generating the levels of transmit and receive attenuation using the level of remote background noise and the local histogram.   
     
     
       23. The process of claim 15, wherein: step (a) further comprises the step of generating, with the controller, a remote histogram based on the remote audio signals; and   step (b) comprises the step of generating the levels of transmit and receive attenuation using the local histogram and the remote histogram.   
     
     
       24. The process of claim 23, wherein step (b) comprises the steps of: (1) generating a level of local background noise using the local histogram;   (2) generating a level of remote background noise using the remote histogram; and   (3) generating the levels of transmit and receive attenuation using the level of local background noise and the level of remote background noise.   
     
     
       25. The process of claim 24, wherein step (b) comprises the steps of: (1) generating an updated level of local background noise, if a variance of the local histogram is less than a specified local threshold;   (2) generating an updated level of remote background noise, if a variance of the remote histogram is less than a specified remote threshold; and   (3) generating the levels of transmit and receive attenuation using the updated levels of local and remote background noise.   
     
     
       26. The process of claim 25, wherein: step (b)(1) comprises the step of generating the updated level of local background noise based on a mean of the local histogram; and   step (b)(2) comprises the step of generating the updated level of remote background noise based on a mean of the remote histogram.   
     
     
       27. The process of claim 15, wherein: step (a) comprises the step of generating the local histogram as a logarithm-based histogram based on energy levels of audio frames of the local audio signals; and   step (b) comprises the steps of: (1) generating a level of local background noise using the local histogram;   (2) receiving, by the controller from the remote node, a level of remote background noise, wherein the level of remote background noise was generated by the remote node from a remote histogram generated by the remote node based on the remote audio signals; and   (3) generating the levels of transmit and receive attenuation using the level of local background noise and the level of remote background noise.     
     
     
       28. The process of claim 27, wherein: step (b)(1) comprises the step of generating an updated level of local background noise based on a mean of the local histogram, if a variance of the local histogram is less than a specified local threshold; and   step (b)(3) comprises the step of generating the levels of transmit and receive attenuation using the updated level of local background noise and the level of remote background noise.

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